Stellar
Evolution (a la Chez Stella)

There is something
odd about this menu, you think. Something very odd. Baffled, you turn to the
waiter. "I'm sorry," you confess, "but I'm new to this. Where I come from, menus
are very different. Can you tell me what I should do?"

The waiter smiles.
"But of course," he answers, "I wouldn't know how to order a hamburger." Then
he looks carefully at the menu. "It is never easy. There is a saying: 'Always
start with blues and follow with reds.' But everyone has different tastes. Some
prefer small stars while others insist that the larger they are the better they
are. I think, if I were you, I'd start with the largest and work my way through
all of them."

You hesitate.
There are no prices on the menu.

"Of course," he
adds, sensing your concern, "you are the guest of Chez Stella. There is no charge."

"Then I'll do
as you suggest," you smile.

"A 60-solar-mass
star, type O5. Plump and ripe. An excellent specimen! Pity they don't last long."
And as he speaks you seem to zoom towards the brightest star until you can easily
see its shape. An apple from thirty meters would appear to be about the same
size. No other stars are visible.

"How long do they
last?" you ask.

"Four million
years, maybe less."

"I'm afraid that's
more time than I have."

"That is what
this is for," he smiles confidentially, and pulls an enormous golden stopwatch
out of his pocket and holds it up so you can see the handsome, old-fashioned
face. "With this watch, I can compress any star's entire existence -- from the
moment it starts burning hydrogen to the instant it dies -- into exactly sixty
seconds."

You nod, wondering
where you could get a watch like that. It would have been very useful on the
blind date you had last Friday.

The waiter raises
the watch. "Ready?"

You turn to the
star. It is hanging alone in black and empty space. "Yes," you say softly.

Immediately you
hear the "tock... tock... tock" of the stopwatch, and you gaze deep into the
distant star. It is a brilliant blue, almost violet, like a blacklight at a
party but more intense. From this distance it appears perfectly smooth. You
blink. It dazzles and fascinates -- hard to look at but impossible to turn away
from.

In
spite of the waiter's claims, nothing seems to be changing. Maybe it grows a
little brighter... maybe it turns a little less blue. It is definitely smoking.
You hadn't noticed before, but it is giving off vast symmetric clouds of what
looks like smoke or dust hanging in the space around the beautiful star.

Suddenly,
after about 52 seconds, it reddens and inflates from the size of an apple to
an enormous yellow-orange balloon eight meters in diameter. Then, just as suddenly,
it collapses again into a hot blue core, leaving behind an expanding cloud of
dust and gas. Something is clearly going on in the center, you think, because
it changes from orange to bluish white once or twice as it puffs larger and
then collapses. It almost seems to be tearing itself apart.

The
flash is so brilliant you could have seen it with your eyes closed. You blink,
dazzled, and stare into empty space. You blink again and realize the star is
gone. There is nothing left at all, except a vast, dense, and expanding cloud
of dust or smoke.

"Is
it gone?" you ask.

"In
a sense, no," the waiter smiles. "About ten percent of its original mass is
still there, trapped in a black hole. The rest has, as you see, been blown away
by the supernova. It isn't a star any more. But, a lot of the material it has
blown off will eventually mix with other dust and gas and eventually end up
in another star - though probably not so large as this was." He pauses a moment,
thinking. "Or it could end up as a planet, or in a person. After all, the oxygen
in you came from a supernova like this one."

"The
oxygen in me?" you start to ask, but he has already turned to the second star.

"This
one has 25 solar masses and you'll see about seven million years of evolution
in one minute." The dust and debris from the first star disappears and is replaced
with a bluish white star about the size of a golf ball seen from thirty meters.

"Tock...
tock... tock..." you hear as you concentrate. It eventually seems to get a little
brighter and maybe a little bigger. It smokes some in those nice symmetric puffs
you saw the first time. Then, in the last six seconds it too puffs up, until
it is a deep-red sphere maybe eight meters across. "How much of it is getting
blown into space?" you ask.

Before
the waiter can answer, the star dies in a brilliant flash that is indistinguishable
from the death of the first star.

You
blink, dazzled into silence for a moment, but soon the questions come flooding
back. "Was it doing the same thing the first one did? Was it changing color
in the beginning? Did it get brighter? And was it getting bigger?" you try to
ask all these questions and more, but the waiter doesn't seem to hear. He has
already started the clock.

This
one is twelve times as massive as the Sun and looks about three centimeters
across from where you are. It remains unchanged for about ninety percent of
its life. Suddenly it balloons into a deep-red ball more than five meters in
diameter. Then, almost as if the balloon had popped, it collapses and turns
blue for several seconds. Finally, it expands, turns red, and dies in a terrible
flash.

"That little gleam
left over is a neutron star," the waiter says, but before you can get a really
good look, the debris disappears and is replaced by a new star. And the clock
is already ticking.